Press devices are machines that typically have vertically moving components generally activated by a ram actuator. Examples of press devices include stamping presses, printing presses, screening presses, and mold casting assemblies.
A typical mold casting assembly is used to create a particular shaped component from molten materials such as plastics or metal. In the metallurgy industry, low pressure mold casting involves the injection of a molten metal into a casting machine typically having a two-piece mold. The mold casting machine can be supported on a carriage so it can be moved to and away from a crucible containing the molten metal. The casting machine may be moved during changing of the casting mold or during servicing of the furnace. Each casting mold is comprised of an upper mold half called the cope and a lower mold half called the drag. The drag and cope are usually constructed of iron, H-13 tool steel or similar metals if casting is performed using metals with a relatively low melting point such as aluminum, zinc, magnesium, copper, lead, and their respective alloys.
Typically, a casting mold is installed onto the casting machine by first placing the mold onto a vertically moveable upper plate called the platen. The drag and cope are kept banded together until the cope can be attached to the platen. After the cope is secured to the movable platen, the movable platen is lowered to rest the drag upon a base plate of the casting machine. The banding about the cope and drag is then removed and the drag is secured to the base plate. Thereafter the mold cavity defined by the cope and drag is opened and closed during casting cycles and the molten metal from the crucible is supplied into the mold cavity during each casting cycle. The molten metal is allowed to cool within the mold cavity before the mold is opened and the casting is removed. Sometimes a special ejector device is used to remove the castings from the mold since the castings often stick to the mold halves.
When the cope is suspended in the open position on the moving platen of the casting machine, there exists a significant amount of potential energy stored in the suspended components and the associated hydraulic cylinders of the machine. Because of this, it is known to use safety die blocks to support and lock the position of the movable platen to prevent movement thereof and maintain the machine in a zero mechanical state, commonly referred to as ZMS. Adjustable jack-type safety die blocks are well known in the art for this purpose and one type of such a safety block is described in U.S. Pat. No. 2,653,560 to Bradhering. However, adjustable jack-type safety blocks are time-consuming to install and can interfere with working space during cleaning or maintenance of the machines. An example of a more automated ratchet-type of safety block device is shown in FIG. 17 of U.S. Pat. No. 5,598,882 to Merrill.